Organometallic compound and organic light-emitting device including the same

ABSTRACT

An organometallic compound includes a hexadentate ligand bonded to a metal atom (M1). An energy level (E3MC) of a 3MC state (triplet metal centered state) of the organometallic compound is higher than an energy level (E3MLCT) of a 3MLCT state (triplet metal-to-ligand charge transfer state) of the organometallic compound.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2018-0046291, filed on Apr. 20, 2018,in the Korean Intellectual Property Office, and entitled:“Organometallic Compound and Organic Light-Emitting Device Including theSame,” is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

Embodiments relate to an organometallic compound and an organiclight-emitting device including the same.

2. Description of the Related Art

Organic light-emitting devices are self-emission devices that producefull-color images, and also have wide viewing angles, high contrastratios, short response times, and excellent characteristics in terms ofbrightness, driving voltage, and response speed, compared to devices inthe art.

An example of such organic light-emitting devices may include a firstelectrode disposed on a substrate, and a hole transport region, anemission layer, an electron transport region, and a second electrode,which are sequentially disposed on the first electrode. Holes providedfrom the first electrode may move toward the emission layer through thehole transport region, and electrons provided from the second electrodemay move toward the emission layer through the electron transportregion. Carriers, such as holes and electrons, recombine in the emissionlayer to produce excitons. These excitons transit from an excited stateto a ground state, thereby generating light.

SUMMARY

Embodiments are directed to an organometallic compound including ahexadentate ligand bonded to a metal atom (M₁). An energy level(E_(3MC)) of a ³MC state (triplet metal centered state) of theorganometallic compound is higher than an energy level (E_(3MLCT)) of a³MLCT state (triplet metal-to-ligand charge transfer state) of theorganometallic compound.

Embodiments are also directed to an organometallic compound representedby Formula 1:

In Formulae 1, 2A, and 2B,

M₁ may be selected from platinum (Pt), palladium (Pd), copper (Cu),silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru),osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu),terbium (Tb), and thulium (Tm),

A₁ to A₆ may each independently be selected from a C₅-C₆₀ carbocyclicgroup and a C₁-C₆₀ heterocyclic group,

L₁ to L₆ may each independently be selected from a single bond, *—O—*′,*—S—*′, *—C(R₁)(R₂)—*′, *—C(R₁)═*′, *═C(R₁)—*′, *—C(R₁)═C(R₂)—*′,*—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₁)—*′, *—N(R₁)—*′, *—P(R₁)—*′,*—Si(R₁)(R₂)—*′, *—P(R₁)(R₂)—*′, and *—Ge(R₁)(R₂)—*′,

a1, a3, and a5 may each independently be selected from 1, 2, and 3,

a2, a4, and a6 may each independently be selected from 0, 1, 2, and 3,

when a2 is 0, A₂ and A₃ may not be linked,

when a4 is 0, A₄ and A₅ may not be linked,

when a6 is 0, A₆ and A₁ may not be linked,

Y₁ to Y₆ may each independently be N or C,

T₁ to T₆ may each independently be selected from a single bond, O, andS,

A₁, A₃, and A₅ may be linked via a clipping linker represented byFormula 2A or 2B,

X₁ may be linked to X₁₀ in Formula 2A or 2B,

X₂ may be linked to X₂₀ in Formula 2A or 2B,

X₃ may be linked to X₃₀ in Formula 2A or 2B,

Y₁₀, Y₂₀, Y₃₀, and Y₄₀ may each independently be N or C(R₃),

L₁₀, L₂₀, and L₃₀ may each independently be selected from a single bond,*—O—*′, *—S—*′, *—C(R₄)(R₅)—*′, *—C(R₄)═*′, *═C(R₄)—*′,*—C(R₄)═C(R₅)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₄)—*′,*—N(R₄)—*′, *—P(R₄)—*′, *—Si(R₄)(R₅)—*′, *—P(R₄)(R₅)—*′, and*—Ge(R₄)(R₅)—*′,

a10, a20, and a30 may each independently be selected from 0, 1, 2, 3, 4,and 5,

R₁ to R₅, R₁₀, R₂₀, R₃₀, R₄₀, R₅₀, and R₆₀ may each independently beselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted C₁-C₆₀ hetero aryloxy group, a substituted orunsubstituted C₁-C₆₀ hetero arylthio group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —B(Q₁)(Q₂), —N(Q₁)(Q₂),—P(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)(Q₁), —S(═O)₂(Q₁), —P(═O)(Q₁)(Q₂), and—P(═S)(Q₁)(Q₂),

R₁ and R₁₀; R₁ and R₂₀; R₁ and R₃₀; R₁ and R₄₀; R₁ and R₅₀; or R₁ andR₆₀ may optionally be linked to form a substituted or unsubstitutedC₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀heterocyclic group,

b10, b20, b30, b40, b50, and b60 may each independently be selected from1, 2, 3, 4, 5, 6, 7, and 8,

* and *′ each indicate a binding site to a neighboring atom,

at least one substituent of the substituted C₅-C₆₀ carbocyclic group,the substituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁),and —P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and—P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independentlybe selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group,a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀hetero aryloxy group, a C₁-C₆₀ hetero arylthio group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a C₁-C₆₀ alkyl group substituted withat least one selected from deuterium, —F, and a cyano group, a C₆-C₆₀aryl group substituted with at least one selected from deuterium, —F,and a cyano group, a biphenyl group, and a terphenyl group.

Embodiments are also directed to an organic light-emitting deviceincluding a first electrode, a second electrode facing the firstelectrode, and an organic layer between the first electrode and thesecond electrode and including an emission layer, wherein the organiclayer includes an organometallic compound, the organometallic compoundincludes a hexadentate ligand bonded to a metal atom (M₁), and an energylevel (E_(3MC)) of a ³MC state (triplet metal centered state) of theorganometallic compound is higher than an energy level (E_(3MLCT)) of a³MLCT state (triplet metal-to-ligand charge transfer state) of theorganometallic compound.

BRIEF DESCRIPTION OF THE DRAWING

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the FIGURE which is a schematic view of an organiclight-emitting device according to an embodiment.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawing; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey exemplary implementations to those skilled in the art.

In the drawing FIGURE, the dimensions of layers and regions may beexaggerated for clarity of illustration. Like reference numerals referto like elements throughout.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

An organometallic compound according to an example embodiment mayinclude a hexadentate ligand bonded to a metal atom (M₁). In an exampleembodiment, an energy level (E_(3MC)) of a ³MC state (triplet metalcentered state) of the organometallic compound is higher than an energylevel (E_(3MLCT)) of a ³MLCT state (triplet metal-to-ligand chargetransfer state) of the organometallic compound.

In an example embodiment, the organometallic compound may satisfy E₃≥5kcal/mol, and E₃ may be defined in Equation 1:

E ₃ =∥E _(3MLCT) |−|E _(3MC)∥.  <Equation 1>

In an example embodiment, the organometallic compound may satisfy E₃≥5kcal/mol. In an example embodiment, the organometallic compound maysatisfy E₃≥8 kcal/mol, for example, E₃≥19 kcal/mol.

In an example embodiment, the hexadentate ligand may include at leastone selected from a 5-membered heterocyclic group and a C₁-C₆₀ condensedheteropolycyclic group including a 5-membered heterocyclic group, and atleast one selected from a 6-membered carbocyclic group, a 6-memberedheterocyclic group, a C₆-C₆₀ condensed polycyclic group including a6-membered carbocyclic group, a C₁-C₆₀ condensed heteropolycyclic groupincluding a 6-membered carbocyclic group, and a C₁-C₆₀ condensedheteropolycyclic group including a 6-membered heterocyclic group.

In an example embodiment, in the hexadentate ligand, at least oneselected from a 5-membered heterocyclic group and a C₁-C₆₀ condensedheteropolycyclic group including a 5-membered heterocyclic group and atleast one selected from a 6-membered carbocyclic group, a 6-memberedheterocyclic group, a C₆-C₆₀ condensed polycyclic group including a6-membered carbocyclic group, a C₁-C₆₀ condensed heteropolycyclic groupincluding a 6-membered carbocyclic group, and a C₁-C₆₀ condensedheteropolycyclic group including a 6-membered heterocyclic group may belinked via a clipping linker.

For example, the hexadentate ligand may have a hemicage structure.

In an example embodiment, M₁ may be selected from platinum (Pt),palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh),iridium (Ir), ruthenium (Ru), osmium (Os), titanium (Ti), zirconium(Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm).

For example, M₁ may be selected from Pt, Pd, Cu, Ag, and Au.

In an example embodiment, when M₁ is iridium (Ir), the organometalliccompound may satisfy E₃≥8 kcal/mol.

In an example embodiment, when M₁ is platinum (Pt), the organometalliccompound may satisfy E₃≥6 kcal/mol.

In an example embodiment, the organometallic compound may satisfy 5kcal/mol≤E₃≤50 kcal/mol, for example, 8 kcal/mol≤E₃≤30 kcal/mol.

Without being bound by theory, it is believed that when theorganometallic compound satisfies the range of E₃, the transitionprobability from the ³MLCT state of the organometallic compound to the³MC state (which is the non-luminescent state) is reduced. Therefore,the stability in the excited state may be enhanced, and the efficiencyand lifespan of the organic light-emitting device including theorganometallic compound may be enhanced.

In an example embodiment, an organometallic compound represented byFormula 1 is provided:

In Formula 1, M₁ may be selected from platinum (Pt), palladium (Pd),copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir),ruthenium (Ru), osmium (Os), titanium (Ti), zirconium (Zr), hafnium(Hf), europium (Eu), terbium (Tb), and thulium (Tm).

In an example embodiment, in Formula 1, M₁ may be selected from Pt, Pd,Ir, Cu, Ag, and Au.

For example, M₁ in Formula 1 may be Pt or Ir, for example.

In Formula 1, A₁ to A₆ may each independently be selected from a C₅-C₆₀carbocyclic group and a C₁-C₆₀ heterocyclic group.

In an example embodiment, in Formula 1, A₁, A₃, and A₅ may be a5-membered heterocyclic group or a C₁-C₆₀ condensed heteropolycyclicgroup including a 5-membered heterocyclic group, and

A₂, A₄, and A₆ may be a 6-membered carbocyclic group, a 6-memberedheterocyclic group, a C₆-C₆₀ condensed polycyclic group including a6-membered carbocyclic group, a C₆-C₆₀ condensed heteropolycyclic groupincluding a 6-membered carbocyclic group, or a C₁-C₆₀ condensedheteropolycyclic group including a 6-membered heterocyclic group.

In an example embodiment, in Formula 1, A₂, A₄, and A₆ may be selectedfrom Formulae 2-1 to 2-9, and A₁, A₃, and A₅ may be selected fromFormulae 2-10 to 2-43:

In Formulae 2-1 to 2-43,

X₂₁ to X₂₃ may each independently be selected from C(R₂₄) and C—*,wherein at least two of X₂₁ to X₂₃ are each independently C—*,

X₂₄ may be N—*, and X₂₅ and X₂₆ may each independently be selected fromC(R₂₄) and C—*, wherein at least one of X₂₅ and X₂₆ is C—*,

X₂₇ and X₂₈ may each independently be selected from N, N(R₂₅), and N—*,and X₂₉ may be selected from C(R₂₄) and C—*, wherein i) at least one ofX₂₇ and X₂₈ is N—* and X₂₉ is C—*, or ii) X₂₇ and X₂₈ may eachindependently be N—* and X₂₉ may be C(R₂₄),

R₂₁ to R₂₅ may respectively be the same as described in connection withR₁₀,

b21 may be selected from 1, 2, and 3,

b22 may be selected from 1, 2, 3, 4, and 5,

b23 may be selected from 1, 2, 3, and 4,

b24 may be selected from 1 and 2, and

* indicates a binding site to a neighboring atom.

In Formula 1, L₁ to L₆ may each independently be selected from a singlebond, *—O—*′, *—S—*′, *—C(R₁)(R₂)—*′, *—C(R₁)═*′, *═C(R₁)—*′,*—C(R₁)═C(R₂)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₁)—*′,*—N(R₁)—*′, *—P(R₁)—*′, *—Si(R₁)(R₂)—*′, *—P(R₁)(R₂)—*′, and*—Ge(R₁)(R₂)—*′,

a1, a3, and a5 may each independently be selected from 1, 2, and 3,

a2, a4, and a6 may each independently be selected from 0, 1, 2, and 3,

when a2 is 0, A₂ and A₃ may not be linked,

when a4 is 0, A₄ and A₅ may not be linked, and

when a6 is 0, A₆ and A₁ may not be linked.

In an example embodiment, in Formula 1, Li to L₆ may each independentlybe selected from a single bond, *—O—*′, *—S—*′, *—C(R₁)(R₂)—*′,*—C(R₁)═*′, *═C(R₁)—*′, *—C(R₁)═C(R₂)—*′, *—C(═O)—*′, *—C(═S)—*′, and*—N(R₁)—*′

In an example embodiment, in Formula 1, a1, a3, and a5 may eachindependently be 1, and a2, a4, and a6 may each independently be 0 or 1.

In an example embodiment, in Formula 1, a2, a4, and a6 may eachindependently be 0.

In an example embodiment, in Formula 1, a2, a4, and a6 may eachindependently be 0,

A₁, A₃, and A₅ may each independently be represented by one of Formulae3-1 to 3-4, and

A₂, A₄, and A₆ may each independently be a group represented by Formula4-1:

In Formulae 3-1 to 3-4,

Y₃₁ may be N or C(R₃₁),

Y₄₁ may be N or C(R₄₁),

R₃₁ to R₃₄ may respectively be the same as described in connection withR₁₀,

R₄₁ may be the same as described in connection with R₂₀, and

* and *′ each indicate a binding site to a neighboring atom.

In Formula 1, Y₁ to Y₆ may each independently be N or C.

In an example embodiment, in Formula 1, Y₁, Y₃, and Y₅ may eachindependently be C or N, and Y₂, Y₄, and Y₆ may each independently be C.

In Formula 1, T₁ to T₆ may each independently be selected from a singlebond, O, and S.

In an example embodiment, in Formula 1, each of T₁ to T₆ may be a singlebond;

T₁ may be selected from O and S, and T₂, T₃, T₄, T₅, and T₆ may be asingle bond;

T₂ may be selected from O and S, and T₁, T₃, T₄, T₅, and T₆ may be asingle bond;

T₃ may be selected from O and S, and T₁, T₂, T₄, T₅, and T₆ may be asingle bond;

T₄ may be selected from O and S, and T₁, T₂, T₃, T₅, and T₆ may be asingle bond;

T₅ may be selected from O and S, and T₁, T₂, T₃, T₄, and T₆ may be asingle bond; or

T₆ may be selected from O and S, and T₁, T₂, T₃, T₄, and T₅ may be asingle bond.

In an example embodiment, in Formula 1, TI, T₃, and T₅ may be a singlebond, and T₂, T₄, and T₆ may be selected from O and S.

In an example embodiment, in Formula 1, each of T₁ to T₆ may be a singlebond.

In Formula 1, A₁, A₃, and A₅ may be linked via a clipping linkerrepresented by Formula 2A or 2B,

X₁ may be linked to X₁₀ in Formula 2A or 2B, e.g., as a single bond,

X₂ may be linked to X₂₀ in Formula 2A or 2B, e.g., as a single bond, and

X₃ may be linked to X₃₀ in Formula 2A or 2B, e.g., as a single bond.

For example, X₁ and X₁₀; X₂ and X₂₀; and X₃ and X₃₀ may form a singlebond.

In Formulae 2A and 2B, Y₁₀, Y₂₀, Y₃₀, and Y₄₀ may each independently beN or C(R₃).

In an example embodiment, in Formulae 2A and 2B, Y₁₀, Y₂₀, and Y₃₀ mayeach independently be C(R₃).

In Formulae 2A and 2B, L₁₀, L₂₀, and L₃₀ may each independently beselected from a single bond, *—O—*′, *—S—*′, *—C(R₄)(R₅)—*′, *—C(R₄)═*′,*═C(R₄)—*′, *—C(R₄)═C(R₅)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′,*—B(R₄)—*′, *—N(R₄)—*′, *—P(R₄)—*′, *—Si(R₄)(R₅)—*′, *—P(R₄)(R₅)—*′, and*—Ge(R₄)(R₅)—*′.

In an example embodiment, in Formulae 2A and 2B, L₁₀, L₂₀, and L₃₀ mayeach independently be *—C(R₄)(R₅)—*′, *—C(R₄)═*′, *═C(R₄)—*′, or*—C(R₄)═C(R₅)—*′.

In Formulae 2A and 2B, a10, a20, and a30 may each independently beselected from 0, 1, 2, 3, 4, and 5.

In an example embodiment, in Formulae 2A and 2B, a10, a20, and a30 mayeach independently be 1 or 2.

For example, in Formulae 2A and 2B, L₁₀, L₂₀, and L₃₀ may eachindependently be *—C(R₄)(R₅)—*′, *—C(R₄)═*′, *═C(R₄)—*I, or*—C(R₄)═C(R₅)—*′, and a10, a20, and a30 may each independently be 1 or2.

In an example embodiment, the clipping linker represented by Formula 2Aor 2B may have any one structure selected from Formulae 5-1 to 5-7:

In Formulae 5-1 to 5-7,

X₁₀, X₂₀, and X₃₀ may respectively be the same as those described inFormula 2A and 2B.

In Formulae 1, 2A, and 2B, R₁ to R₅, R₁₀, R₂₀, R₃₀, R₄₀, R₅₀, and R₆₀may each independently be selected from hydrogen, deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedC₁-C₆₀ hetero aryloxy group, a substituted or unsubstituted C₁-C₆₀hetero arylthio group, a substituted or unsubstituted monovalentnon-aromatic condensed polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁)(Q₂)(Q₃), —B(Q₁)(Q₂), —N(Q₁)(Q₂), —P(Q₁)(Q₂), —C(═O)(Q₁),—S(═O)(Q₁), —S(═O)₂(Q₁), —P(═O)(Q₁)(Q₂), and —P(═S)(Q₁)(Q₂),

R₁ and R₁₀; R₁ and R₂₀; R₁ and R₃₀; R₁ and R₄₀; R₁ and R₅₀; or R₁ andR₆₀ may optionally be linked to form a substituted or unsubstitutedC₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀heterocyclic group,

b10, b20, b30, b40, b50, and b60 may each independently be 1, 2, 3, 4,5, 6, 7, or 8,

* and *′ each indicate a binding site to a neighboring atom,

at least one substituent of the substituted C₅-C₆₀ carbocyclic group,the substituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁),—S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁) and—P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁) and —P(═O)(Q₃₁)(Q₃₂), and

Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independentlybe selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group,a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀hetero aryloxy group, a C₁-C₆₀ hetero arylthio group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a C₁-C₆₀ alkyl group substituted withat least one selected from deuterium, —F, and a cyano group, a C₆-C₆₀aryl group substituted with at least one selected from deuterium, —F,and a cyano group, a biphenyl group, and a terphenyl group.

In an example embodiment, in Formulae 1, 2A, and 2B, R₁ to R₅ may eachindependently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a cyano group, a C₁-C₂₀ alkylgroup, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a cyano group, aphenyl group, and a biphenyl group;

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, an indacenylgroup, an acenaphthenyl group, a fluorenyl group, a spiro-bifluorenylgroup, a benzofluorenyl group, a dibenzofluorenyl group, a carbazolylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, and a dibenzocarbazolyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, an indacenylgroup, an acenaphthenyl group, a fluorenyl group, a spiro-bifluorenylgroup, a benzofluorenyl group, a dibenzofluorenyl group, a carbazolylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, and a dibenzocarbazolyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a cyanogroup, a phenyl group, and a biphenyl group.

In an example embodiment, in Formula 1, R₁₀, R₂₀, R₃₀, and R₄₀ may eachindependently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a cyano group, a methyl group, anethyl group, an n-propyl group, an isopropyl group, an n-butyl group, aniso-butyl group, a sec-butyl group, and a tert-butyl group;

a methyl group, an ethyl group, an n-propyl group, an isopropyl group,an n-butyl group, an iso-butyl group, a sec-butyl group, and atert-butyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, and a cyano group; and

a phenyl group, a naphthyl group, and a pyridinyl group.

In an example embodiment, in Formula 1, a ligand may be represented byFormula 1-1 or 1-2, except for M₁:

In Formulae 1-1 and 1-2,

A₁ to A₆, L₁, L₃, L₅, a1, a3, a5, Y₁₀, Y₂₀, Y₃₀, Y₄₀, L₁₀, L₂₀, L₃₀, R₁to R₅, R₁₀, R₂₀, R₃₀, R₄₀, R₅₀, R₆₀, b10, b20, b30, b40, b50, and b60may respectively be the same as described above,

Y₁ to Y₆ may each independently be N or C, and

Y₁ to Y₆ may be bound to M₁ in Formula 1.

For example, Y₁ to Y₆ may be coordinately or covalently bound to M₁ inFormula 1.

In an example embodiment, the organometallic compound may be selectedfrom Compounds 1 to 28, for example:

The organometallic compound represented by Formula 1 has a structure inwhich A₁, A₃, and A₅ in Formula 1 are linked via a clipping linkerrepresented by Formula 2A or 2B, and has a hexadentate ligand having athree-dimensional hemicage structure. Thus, the stability and durabilityof the compound may be enhanced even in the excited state.

In addition, the clipping linker links the carbocyclic group orheterocyclic group included in the ligand. Thus, when the organometalliccompound is applied to the organic light-emitting device, it may bepossible to prevent the phenomenon that the triplet exciton transits tothe ³MC state (which is the non-luminescent state) due to ligandrupture. Therefore, the stability in the excited state may be enhanced,and the lifespan and efficiency of the organic light-emitting device maybe enhanced.

In addition, in one embodiment, the organometallic compound representedby Formula 1 may satisfy the range of E₃. At this time, the transitionprobability of the organometallic compound represented by Formula 1 fromthe ³MCLC state to the ³MC state that is the non-luminescent state isreduced, and thus, the stability in the excited state is excellent.Therefore, the efficiency and lifespan of the organic light-emittingdevice including the organometallic compound may be enhanced.

The organometallic compound may emit blue light. For example, theorganometallic compound may emit blue light having a wavelength ofmaximum emission of about 440 nm to about 490 nm (bottom-emissionCIE_(x,y) color coordinates 0.05, 0.3 to 0.18, 0.08), for example.Therefore, the organometallic compound represented by Formula 1 may beused to manufacture an organic light-emitting device that emits bluelight.

A synthesis method for the organometallic compound represented byFormula 1 would be apparent to those of ordinary skill in the art.

At least one of the organometallic compound represented by Formula 1 maybe used between a pair of electrodes of an organic light-emittingdevice. For example, the organometallic compound may be included in anemission layer. The organometallic compound may act as a dopant in theemission layer.

According to an example embodiment, there is provided the organiclight-emitting device including: the first electrode, the secondelectrode facing the first electrode, and the organic layer between thefirst electrode and the second electrode and including the emissionlayer, wherein the organic layer includes the organometallic compound.The organometallic compound includes a hexadentate ligand bonded to ametal atom (M₁), and an energy level (E_(3MC)) of a ³MC state (tripletmetal centered state) of the organometallic compound is higher than anenergy level (E_(3MLCT)) of a ³MLCT state (triplet metal-to-ligandcharge transfer state) of the organometallic compound.

The organometallic compound included in the organic light-emittingdevice may be understood by referring to the description of theorganometallic compound.

For example, the organometallic compound may satisfy E₃≥5 kcal/mol,wherein E₃ may be defined in Equation 1:

E ₃ =∥E _(3MLCT) |−|E _(3MC)∥  <Equation 1>

According to an example embodiment, there is provided an organiclight-emitting device including: a first electrode, a second electrodefacing the first electrode, and an organic layer disposed between thefirst electrode and the second electrode, the organic layer including anemission layer, wherein the organic layer includes at least oneorganometallic cyclic compound represented by Formula 1.

The expression “(an organic layer) includes at least one organometalliccompound” used herein may include a case in which “(an organic layer)includes identical compounds represented by Formula 1” and a case inwhich “(an organic layer) includes two or more different organometalliccompounds represented by Formula 1.”

For example, the organic layer may include, as the organometalliccompound, only Compound 1. In this regard, Compound 1 may exist in anemission layer of the organic light-emitting device. In an exampleembodiment, the organic layer may include, as the organometalliccompound, Compound 1 and Compound 2. In this regard, Compound 1 andCompound 2 may exist in an identical layer (for example, Compound 1 andCompound 2 may all exist in an emission layer), or different layers (forexample, Compound 1 may exist in an emission layer and Compound 2 mayexist in an electron transport region).

According to an example embodiment,

the first electrode of the organic light-emitting device may be ananode,

the second electrode of the organic light-emitting device may be acathode,

the organic layer may include a hole transport region between the firstelectrode and the emission layer and an electron transport regionbetween the emission layer and the second electrode,

the hole transport region may include a hole injection layer, a holetransport layer, an emission auxiliary layer, an electron blockinglayer, or any combination thereof, and

the electron transport region may include a hole blocking layer, anelectron transport layer, an electron injection layer, or anycombination thereof.

The term “organic layer” used herein refers to a single layer and/or aplurality of layers disposed between the first electrode and the secondelectrode of the organic light-emitting device. A material included inthe “organic layer” may include materials other than an organicmaterial.

In an example embodiment, the emission layer may include theorganometallic compound represented by Formula 1.

In an example embodiment, the emission layer may include theorganometallic compound represented by Formula 1, and may include ahost. An amount of the host in the emission layer may be greater thanthat of the organometallic compound in the emission layer. The host mayinclude, for example, a silyl-containing compound, a phosphineoxide-containing compound, or a combination thereof.

In an example embodiment, the emission layer may emit bluephosphorescence having a wavelength of maximum emission in a range ofabout 440 nm to about 490 nm.

In an example embodiment, the hole transport region may include anelectron blocking layer, which may include the organometallic compound.

In an example embodiment, the hole transport region may include a holetransport layer, which may include a carbazole-based compound.

In an example embodiment, the hole transport region may include ap-dopant of which a lowest unoccupied molecular orbital (LUMO) energylevel of less than about −3.5 eV.

In an example embodiment, the electron transport region may include ahole blocking layer, which may directly contact the emission layer. Thehole blocking layer may include a phosphine oxide-containing compound ora silyl-containing compound.

DESCRIPTION OF THE FIGURE

The FIGURE a schematic view of an organic light-emitting device 10according to an embodiment. According to an example embodiment, theorganic light-emitting device 10 includes a first electrode 110, anorganic layer 150, and a second electrode 190.

Hereinafter, the structure of the organic light-emitting device 10according to an embodiment and a method of manufacturing the organiclight-emitting device 10 will be described in connection with theFIGURE.

[First Electrode 110]

In the FIGURE, a substrate may be additionally disposed under the firstelectrode 110 or above the second electrode 190. The substrate may be,for example, a glass substrate or a plastic substrate, which may haveexcellent mechanical strength, thermal stability, transparency, surfacesmoothness, ease of handling, and water resistance.

The first electrode 110 may be formed by, for example, depositing orsputtering a material for forming the first electrode 110 on thesubstrate. When the first electrode 110 is an anode, the material for afirst electrode may be selected from, for example, materials with a highwork function to facilitate hole injection.

The first electrode 110 may be a reflective electrode, asemi-transmissive electrode, or a transmissive electrode. When the firstelectrode 110 is a transmissive electrode, a material for forming afirst electrode may be selected from, for example, indium tin oxide(ITO), indium zinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), acombination thereof, etc. In an example embodiment, when the firstelectrode 110 is a semi-transmissive electrode or a reflectiveelectrode, a material for forming a first electrode may be selectedfrom, for example, magnesium (Mg), silver (Ag), aluminum (Al),aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In),magnesium-silver (Mg—Ag), a combination thereof, etc.

The first electrode 110 may have a single-layered structure, or amulti-layered structure including two or more layers. For example, thefirst electrode 110 may have a three-layered structure of ITO/Ag/ITO.

[Organic Layer 150]

The organic layer 150 is disposed on the first electrode 110. Theorganic layer 150 may include an emission layer.

The organic layer 150 may include a hole transport region between thefirst electrode 110 and the emission layer, and an electron transportregion between the emission layer and the second electrode 190.

[Hole Transport Region in Organic Layer 150]

The hole transport region may have, for example, i) a single-layeredstructure including a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The hole transport region may include at least one layer selected from ahole injection layer, a hole transport layer, an emission auxiliarylayer, and an electron blocking layer.

For example, the hole transport region may have a single-layeredstructure including a single layer including a plurality of differentmaterials, or a multi-layered structure having a hole injectionlayer/hole transport layer structure, a hole injection layer/holetransport layer/emission auxiliary layer structure, a hole injectionlayer/emission auxiliary layer structure, a hole transportlayer/emission auxiliary layer structure, or a hole injection layer/holetransport layer/electron blocking layer structure, wherein for eachstructure, constituting layers may be sequentially stacked from thefirst electrode 110 in the stated order.

The hole transport region may include at least one selected from, forexample, m-MTDATA, TDATA, 2-TNATA, NPB(NPD), P3-NPB, TPD, Spiro-TPD,Spiro-NPB, methylated-NPB, TAPC, HMTPD,4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA),polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (PANI/CSA),polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound representedby Formula 201, and a compound represented by Formula 202:

In Formulae 201 and 202,

L₂₀₁ to L₂₀₄ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted orunsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstitutedC₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xa1 to xa4 may each independently be an integer of 0 to 3,

xa5 may be an integer of 1 to 10, and

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from asubstituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted orunsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group.

For example, in Formula 202, R₂₀₁ and R₂₀₂ may optionally be linked viaa single bond, a dimethyl-methylene group, or a diphenyl-methylenegroup, and R₂₀₃ and R₂₀₄ may optionally be linked via a single bond, adimethyl-methylene group, or a diphenyl-methylene group.

In an example embodiment, in Formulae 201 and 202,

L₂₀₁ to L₂₀₅ may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthenylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a dibenzosilolylene group, and apyridinylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthenylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a dibenzosilolylene group, and apyridinylene group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthenyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

In an example embodiment, xa1 to xa4 may each independently be 0, 1, or2.

In an example embodiment, xa5 may be 1, 2, 3, or 4.

In an example embodiment, R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independentlybe selected from:

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthenyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenalenyl group, a phenanthrenyl group, an anthracenyl group,a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a naphthacenyl group, a picenyl group, a perylenylgroup, a pentaphenyl group, a hexacenyl group, a pentacenyl group, arubicenyl group, a coronenyl group, an ovalenyl group, a thiophenylgroup, a furanyl group, a carbazolyl group, an indolyl group, anisoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthenyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenalenyl group, a phenanthrenyl group, an anthracenyl group,a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a naphthacenyl group, a picenyl group, a perylenylgroup, a pentaphenyl group, a hexacenyl group, a pentacenyl group, arubicenyl group, a coronenyl group, an ovalenyl group, a thiophenylgroup, a furanyl group, a carbazolyl group, an indolyl group, anisoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthenyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may respectively be the same as described above.

In an example embodiment, in Formula 201, at least one selected fromR₂₀₁ to R₂₀₃ may each independently be selected from:

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkylgroup, a phenyl group substituted with —F, a naphthyl group, a fluorenylgroup, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranylgroup, and a dibenzothiophenyl group.

In an example embodiment, in Formula 202, i) R₂₀₁ and R₂₀₂ may be linkedvia a single bond, and/or ii) R₂₀₃ and R₂₀₄ may be linked via a singlebond.

In an example embodiment, in Formula 202, at least one selected fromR₂₀₁ to R₂₀₄ may be selected from:

a carbazolyl group; and

a carbazolyl group substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, acarbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group.

The compound represented by Formula 201 may be represented by Formula201A:

For example, the compound represented by Formula 201 may be representedby Formula 201A(1):

In an example embodiment, the compound represented by Formula 201 may berepresented by Formula 201A-1:

In an example embodiment, the compound represented by Formula 202 may berepresented by Formula 202A:

In an example embodiment, the compound represented by Formula 202 may berepresented by Formula 202A-1:

In Formulae 201A, 201A(1), 201A-1, 202A, and 202A-1,

L₂₀₁ to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂ to R₂₀₄ may respectively be thesame as described above,

R₂₁₁ and R₂₁₂ may respectively be the same in connection with R₂₀₃.

R₂₁3 to R₂₁₇ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthenyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group.

The hole transport region may include at least one compound selectedfrom Compounds HT1 to HT39:

A thickness of the hole transport region may be in a range of, forexample, about 100 Å to about 10,000 Å, for example, about 100 Å toabout 1,000 Å. When the hole transport region includes at least one of ahole injection layer and a hole transport layer, a thickness of the holeinjection layer may be in a range of, for example, about 100 Å to about9,000 Å, for example, about 100 Å to about 1,000 Å, and a thickness ofthe hole transport layer may be in a range of, for example, about 50 Åto about 2,000 Å, for example about 100 Å to about 1,500 Å. When thethicknesses of the hole transport region, the hole injection layer, andthe hole transport layer are within these ranges, satisfactory holetransporting characteristics may be obtained without a substantialincrease in driving voltage.

The emission auxiliary layer may increase light-emission efficiency bycompensating for an optical resonance distance according to thewavelength of light emitted by an emission layer, and the electronblocking layer may block the flow of electrons from an electrontransport region. The emission auxiliary layer and the electron blockinglayer may include the materials as described above.

[p-Dopant]

The hole transport region may include a charge-generation material forthe improvement of conductive properties. The charge-generation materialmay be homogeneously or non-homogeneously dispersed in the holetransport region.

The charge-generation material may be, for example, a p-dopant.

In an example embodiment, the p-dopant may have a LUMO energy level ofless than about −3.5 eV.

The p-dopant may include at least one selected from a quinonederivative, a metal oxide, and a cyano group-containing compound, forexample.

For example, the p-dopant may include at least one selected from

a quinone derivative, such as tetracyanoquinodimethane (TCNQ) or2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ);

a metal oxide, such as tungsten oxide or molybdenum oxide;

1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and

a compound represented by Formula 221 below:

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group, wherein at least oneselected from R₂₂₁ to R₂₂₃ may have at least one substituent selectedfrom a cyano group, —F, —Cl, —Br, —I, a C₁-C₂₀ alkyl group substitutedwith —F, a C₁-C₂₀ alkyl group substituted with —C₁, a C₁-C₂₀ alkyl groupsubstituted with —Br, and a C₁-C₂₀ alkyl group substituted with —I.

[Emission Layer in Organic Layer 150]

When the organic light-emitting device 10 is a full-color organiclight-emitting device, the emission layer may be patterned into one ormore of, for example, a red emission layer, a green emission layer, or ablue emission layer, according to a sub-pixel. In an example embodiment,the emission layer may have a stacked structure of two or more layersselected from a red emission layer, a green emission layer, and a blueemission layer, in which the two or more layers contact each other orare separated from each other. In an example embodiment, the emissionlayer may include two or more materials selected from a redlight-emitting material, a green light-emitting material, and a bluelight-emitting material, in which the two or more materials are mixedwith each other in a single layer to emit white light.

The emission layer may include a host and a dopant. The dopant mayinclude at least one selected from a phosphorescent dopant and afluorescent dopant. The phosphorescent dopant may include anorganometallic compound represented by Formula 1.

An amount of the dopant in the emission layer may be in a range of about0.01 parts by weight to about 5 parts by weight based on 100 parts byweight of the host, for example.

A thickness of the emission layer may be in a range of, for example,about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å.When the thickness of the emission layer is within this range, excellentlight-emission characteristics may be obtained without a substantialincrease in driving voltage.

[Host in Emission Layer]

In an example embodiment, the host may include a compound represented byFormula 301 below.

[Ar₃₀₁]_(xb11)[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21)  <Formula 301>

In Formula 301,

Ar₃₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xb11 may be 1, 2, or 3,

L₃₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group;

xb1 may be an integer of 0 to 5,

R₃₀₁ may be selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂),—B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),

xb21 may be an integer of 1 to 5, and

Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group, for example.

In an example embodiment, in Formula 301, Ar301 may be selected from:

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a naphthacenegroup, a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group, and a dibenzothiophenegroup; and

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a naphthacenegroup, a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group, and a dibenzothiophenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group, for example.

In Formula 301, when xb11 is two or more, two or more of Ar₃₀₁(s) may belinked via a single bond.

In an example embodiment, the compound represented by Formula 301 may berepresented by Formula 301-1 or 301-2:

In Formulae 301-1 to 301-2,

A₃₀₁ to A₃₀₄ may each independently be selected from a benzene, anaphthalene, a phenanthrene, a fluoranthene, a triphenylene, a pyrene, achrysene, a pyridine, a pyrimidine, an indene, a fluorene, aspiro-bifluorene, a benzofluorene, a dibenzofluorene, an indole, acarbazole, benzocarbazole, dibenzocarbazole, a furan, a benzofuran, adibenzofuran, a naphthofuran, a benzonaphthofuran, dinaphthofuran, athiophene, a benzothiophene, a dibenzothiophene, a naphthothiophene, abenzonaphthothiophene, and a dinaphthothiophene,

X₃₀₁ may be O, S, or N-[(L₃₀₄)_(xb4)-R₃₀₄],

R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, R₃₀₁, and Q₃₁ to Q₃₃ may respectively be the same asdescribed above,

L₃₀₂ to L₃₀₄ may respectively be the same as described in connectionwith L₃₀₁,

xb2 to xb4 may respectively be the same as described in connection withxb1, and

R₃₀₂ to R₃₀₄ may respectively be the same as described in connectionwith R₃₀₁.

For example, in Formulae 301, 301-1, and 301-2, L₃₀₁ to L₃₀₄ may eachindependently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may respectively be the same as described above.

In an example embodiment, in Formulae 301, 301-1, and 301-2, R₃₀₁ toR₃₀₄ may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may respectively be the same as described above.

In an example embodiment, the host may include an alkaline earth metalcomplex. For example, the host may be selected from a Be complex (forexample, Compound H55), a Mg complex, and a Zn complex.

The host may include at least one selected from9,10-di(2-naphthyl)anthracene (ADN),2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN),9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN),4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene(mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and Compounds H1 to H55,for example:

In an example embodiment, the host may include at least one selectedfrom a silicon-containing compound (for example, BCPDS or the like) anda phosphine oxide-containing compound (for example, POPCPA or the like).

In an example embodiment, the host may include only one compound, or twoor more different compounds (for example, a host may include BCPDS andPOPCPA).

[Phosphorescent Dopant Included in Emission Layer in Organic Layer 150]

The phosphorescent dopant may include an organometallic compoundrepresented by Formula 1 above.

[Electron Transport Region in Organic Layer 150]

The electron transport region may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron transport region may include at least one selected from abuffer layer, a hole blocking layer, an electron control layer, anelectron transport layer, and an electron injection layer, for example.

For example, the electron transport region may have an electrontransport layer/electron injection layer structure, a hole blockinglayer/electron transport layer/electron injection layer structure, anelectron control layer/electron transport layer/electron injection layerstructure, or a buffer layer/electron transport layer/electron injectionlayer structure, wherein for each structure, constituting layers may besequentially stacked from an emission layer.

The electron transport region (for example, a buffer layer, a holeblocking layer, an electron control layer, or an electron transportlayer in the electron transport region) may include, for example, ametal-free compound containing at least one π electron-depletednitrogen-containing ring.

The “n electron-depleted nitrogen-containing ring” indicates a C₁-C₆₀heterocyclic group having at least one *—N═*′ moiety as a ring-formingmoiety.

For example, the “n electron-depleted nitrogen-containing ring” may bei) a 5-membered to 7-membered heteromonocyclic group having at least one*—N═*′ moiety, ii) a heteropolycyclic group in which two or more5-membered to 7-membered heteromonocyclic groups each having at leastone *—N═*′ moiety are condensed with each other, or iii) aheteropolycyclic group in which at least one of 5-membered to 7-memberedheteromonocyclic groups, each having at least one *—N═*′ moiety, iscondensed with at least one C₅-C₆₀ carbocyclic group.

Examples of the π electron-depleted nitrogen-containing ring include animidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, anisoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, anindazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, aphthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline,a phenanthridine, an acridine, a phenanthroline, a phenazine, abenzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, atriazole, a tetrazole, an oxadiazole, a triazine, thiadiazol, animidazopyridine, an imidazopyrimidine, and an azacarbazole.

For example, the electron transport region may include a compoundrepresented by Formula 601:

[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21)  <Formula 601>

In Formula 601,

Ar₆₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xe11l may be 1, 2, or 3,

L₆₀₁ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group;

xe1 may be an integer of 0 to 5,

R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═)(Q₆₀₁),—S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂),

Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or anaphthyl group, and

xe21 may be an integer of 1 to 5.

In an example embodiment, at least one of Ar₆₀₁(s) in the number of xe11and R₆₀₁(s) in the number of xe21 may include the 7r electron-depletednitrogen-containing ring.

In an example embodiment, ring Ar₆₀₁ in Formula 601 may be selectedfrom:

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, a naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, a phenanthroline group, a phenazine group, abenzimidazole group, an isobenzothiazole group, a benzoxazole group, anisobenzoxazole group, a triazole group, a tetrazole group, an oxadiazolegroup, a triazine group, a thiadiazole group, an imidazopyridine group,an imidazopyrimidine group, and an azacarbazole group; and

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, a naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, a phenanthroline group, a phenazine group, abenzimidazole group, an isobenzothiazole group, a benzoxazole group, anisobenzoxazole group, a triazole group, a tetrazole group, an oxadiazolegroup, a triazine group, a thiadiazole group, an imidazopyridine group,an imidazopyrimidine group, and an azacarbazole group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group,—Si(Q₃₁)(Q₃₂)(Q₃₃), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

When xe11l in Formula 601 is two or more, two or more Ar₆₀₁(s) may belinked via a single bond.

In an example embodiment, Ar₆₀₁ in Formula 601 may be an anthracenegroup.

In an example embodiment, a compound represented by Formula 601 may berepresented by Formula 601-1:

In Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), and X₆₁₆ may be N orC(R₆₁₆), wherein at least one selected from X₆₁₄ to X₆₁₆ may be N,

L₆₁₁ to L₆₁₃ may respectively be the same as described in connectionwith L₆₀₁,

xe611 to xe613 may respectively be the same as described in connectionwith xe1,

R₆₁₁ to R₆₁₃ may respectively be the same as described in connectionwith R₆₀₁, and

R₆₁₄ to R₆₁₆ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In an example embodiment, L₆₀₁ and L₆₁₁ to L₆₁₃ in Formulae 601 and601-1 may each independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, and an azacarbazolyl group.

In an example embodiment, xe1 and xe611 to xe613 in Formulae 601 and601-1 may each independently be 0, 1, or 2.

In an example embodiment, in Formulae 601 and 601-1, R₆₀₁ and R₆₁₁ toR₆₁₃ may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group; and

—S(═O)₂(Q₆₀₁) and —P(═O)(Q₆₀₁)(Q₆₀₂), and

Q₆₀₁ and Q₆₀₂ may respectively be the same as described above.

The electron transport region may include at least one compound selectedfrom Compounds ET1 to ET36, for example:

In an example embodiment, the electron transport region may include atleast one compound selected from, for example,2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-diphenyl-1,10-phenanthroline (Bphen), Alq3, BAlq,3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ), and NTAZ.

In an example embodiment, the electron transport region may include, forexample, a phosphine oxide-containing compound (for example, TSPO1 orthe like). In an example embodiment, the phosphine oxide-containingcompound may be used in a hole blocking layer in the electron transportregion, for example.

A thickness of the buffer layer, the hole blocking layer, or theelectron control layer may be in a range of, for example, about 20 Å toabout 1,000 Å, for example, about 30 Å to about 300 Å. When thethicknesses of the buffer layer, the hole blocking layer, and theelectron control layer are within these ranges, the electron blockinglayer may have excellent electron blocking characteristics or electroncontrol characteristics without a substantial increase in drivingvoltage.

A thickness of the electron transport layer may be in a range of, forexample, about 100 Å to about 1,000 Å, for example, about 150 Å to about500 Å. When the thickness of the electron transport layer is within therange described above, the electron transport layer may havesatisfactory electron transport characteristics without a substantialincrease in driving voltage.

The electron transport region (for example, the electron transport layerin the electron transport region) may include a metal-containingmaterial.

The metal-containing material may include at least one selected fromalkali metal complex and alkaline earth-metal complex. The alkali metalcomplex may include a metal ion selected from, for example, a Li ion, aNa ion, a K ion, a Rb ion, and a Cs ion, and the alkaline earth-metalcomplex may include a metal ion selected from, for example, a Be ion, aMg ion, a Ca ion, a Sr ion, and a Ba ion. A ligand coordinated with themetal ion of the alkali metal complex or the alkaline earth-metalcomplex may be selected from, for example, a hydroxy quinoline, ahydroxy isoquinoline, a hydroxy benzoquinoline, a hydroxy acridine, ahydroxy phenanthridine, a hydroxy phenyloxazole, a hydroxyphenylthiazole, a hydroxy diphenyloxadiazole, a hydroxydiphenylthiadiazol, a hydroxy phenylpyridine, a hydroxyphenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, aphenanthroline, and a cyclopentadiene.

For example, the metal-containing material may include a Li complex. TheLi complex may include, for example, Compound ET-D1 (lithium quinolate,LiQ) or ET-D2.

The electron transport region may include an electron injection layerthat facilitates injection of electrons from the second electrode 190.The electron injection layer may directly contact the second electrode190.

The electron injection layer may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron injection layer may include, for example, an alkali metal,an alkaline earth metal, a rare earth metal, an alkali metal compound,an alkaline earth-metal compound, a rare earth metal compound, an alkalimetal complex, an alkaline earth-metal complex, a rare earth metalcomplex, or a combination thereof.

The alkali metal may be selected from, for example, Li, Na, K, Rb, andCs. In an example embodiment, the alkali metal may be Li, Na, or Cs. Inan example embodiment, the alkali metal may be Li or Cs.

The alkaline earth metal may be selected from, for example, Mg, Ca, Sr,and Ba.

The rare earth metal may be selected from, for example, Sc, Y, Ce, Tb,Yb, and Gd.

The alkali metal compound, the alkaline earth-metal compound, and therare earth metal compound may be selected from, for example, oxides andhalides (for example, fluorides, chlorides, bromides, or iodides) of thealkali metal, the alkaline earth-metal, and the rare earth metal.

The alkali metal compound may be selected from, for example, alkalimetal oxides such as Li₂O, Cs₂O, or K₂O, and alkali metal halides, suchas LiF, NaF, CsF, KF, LiI, NaI, CsI, or KI. In an example embodiment,the alkali metal compound may be selected from LiF, Li₂O, NaF, LiI, NaI,CsI, and KI.

The alkaline earth-metal compound may be selected from, for example,alkaline earth-metal oxides, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O(0<x<1), or Ba_(x)Ca_(1-x)O (0<x<1). In an example embodiment, thealkaline earth-metal compound may be selected from BaO, SrO, and CaO.

The rare earth metal compound may be selected from, for example, YbF₃,ScF₃, Sc₂O₃, Y₂O₃, Ce₂O₃, GdF₃, and TbF₃. In an example embodiment, therare earth metal compound may be selected from YbF₃, ScF₃, TbF₃, YbI₃,ScI₃, and TbI₃.

The alkali metal complex, the alkaline earth-metal complex, and the rareearth metal complex may include an ion of alkali metal, alkalineearth-metal, and rare earth metal as described above, and a ligandcoordinated with a metal ion of the alkali metal complex, the alkalineearth-metal complex, or the rare earth metal complex may be selectedfrom, for example, hydroxy quinoline, hydroxy isoquinoline, hydroxybenzoquinoline, hydroxy acridine, hydroxy phenanthridine, hydroxyphenyloxazole, hydroxy phenylthiazole, hydroxy diphenyloxadiazole,hydroxy diphenylthiadiazol, hydroxy phenylpyridine, hydroxyphenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine,phenanthroline, and cyclopentadiene.

The electron injection layer may include or consist of, for example, analkali metal, an alkaline earth metal, a rare earth metal, an alkalimetal compound, an alkaline earth-metal compound, a rare earth metalcompound, an alkali metal complex, an alkaline earth-metal complex, arare earth metal complex, or a combination thereof, as described above.In an example embodiment, the electron injection layer may include anorganic material. When the electron injection layer includes an organicmaterial, then an alkali metal, an alkaline earth metal, a rare earthmetal, an alkali metal compound, an alkaline earth-metal compound, arare earth metal compound, an alkali metal complex, an alkalineearth-metal complex, a rare earth metal complex, or a combinationthereof may be homogeneously or non-homogeneously dispersed in a matrixincluding the organic material.

A thickness of the electron injection layer may be in a range of, forexample, about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å.When the thickness of the electron injection layer is within the rangedescribed above, the electron injection layer may have satisfactoryelectron injection characteristics without a substantial increase indriving voltage.

[Second Electrode 190]

The second electrode 190 may be disposed on the organic layer 150 havingsuch a structure. The second electrode 190 may be a cathode which is anelectron injection electrode, and in this regard, a material for formingthe second electrode 190 may be selected from, for example, metal, analloy, an electrically conductive compound, and a combination thereof,which may have a relatively low work function.

The second electrode 190 may include at least one selected from, forexample, lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al),aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In),magnesium-silver (Mg—Ag), ITO, and IZO. The second electrode 190 may bea transmissive electrode, a semi-transmissive electrode, or a reflectiveelectrode.

The second electrode 190 may have a single-layered structure, or amulti-layered structure including two or more layers.

Layers constituting the hole transport region, an emission layer, andlayers constituting the electron transport region may be formed in acertain region by using one or more suitable methods selected from, forexample, vacuum deposition, spin coating, casting, Langmuir-Blodgett(LB) deposition, ink-jet printing, laser-printing, and laser-inducedthermal imaging.

When layers constituting the hole transport region, an emission layer,and layers constituting the electron transport region are formed byvacuum deposition, the deposition may be performed, for example, at adeposition temperature of about 100° C. to about 500° C., a vacuumdegree of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition speed ofabout 0.01 Å/sec to about 100 Å/sec by taking into account a material tobe included in a layer to be formed, and the structure of a layer to beformed.

When layers constituting the hole transport region, an emission layer,and layers constituting the electron transport region are formed by spincoating, the spin coating may be performed, for example, at a coatingspeed of about 2,000 rpm to about 5,000 rpm and at a heat treatmenttemperature of about 80° C. to about 200° C. by taking into account amaterial to be included in a layer to be formed, and the structure of alayer to be formed.

General Definition of Substituents

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear orbranched aliphatic saturated hydrocarbon monovalent group having 1 to 60carbon atoms, and examples thereof include a methyl group, an ethylgroup, a propyl group, an isobutyl group, a sec-butyl group, atert-butyl group, a pentyl group, an isoamyl group, and a hexyl group.The term “C₁-C₆₀ alkylene group” as used herein refers to a divalentgroup having the same structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbongroup having at least one carbon-carbon double bond in the middle or atthe terminus of the C₂-C₆₀ alkyl group, and examples thereof include anethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀alkenylene group” as used herein refers to a divalent group having thesame structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbongroup having at least one carbon-carbon triple bond in the middle or atthe terminus of the C₂-C₆₀ alkyl group, and examples thereof include anethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group”as used herein refers to a divalent group having the same structure asthe C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalentgroup represented by -OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group),and examples thereof include a methoxy group, an ethoxy group, and anisopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalentsaturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, andexamples thereof include a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term“C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent grouphaving the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to amonovalent monocyclic group having at least one heteroatom selected fromN, O, Si, P, and S as a ring-forming atom and 1 to 10 carbon atoms, andexamples thereof include a 1,2,3,4-oxatriazolidinyl group, atetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term“C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalentgroup having the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term C₃-C₁₀ cycloalkenyl group used herein refers to a monovalentmonocyclic group that has 3 to 10 carbon atoms and at least onecarbon-carbon double bond in the ring thereof and no aromaticity, andexamples thereof include a cyclopentenyl group, a cyclohexenyl group,and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group” asused herein refers to a divalent group having the same structure as theC₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one carbon-carbon double bond in its ring. Non-limitingexamples of the C₁-C₁₀ heterocycloalkenyl group include a4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, anda 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein refers to a divalent group having the samestructure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms, and aC₆-C₆₀ arylene group used herein refers to a divalent group having acarbocyclic aromatic system having 6 to 60 carbon atoms. Non-limitingexamples of the C₆-C₆₀ aryl group include a phenyl group, a naphthylgroup, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, anda chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylenegroup each include two or more rings, the rings may be fused to eachother.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalentgroup having a carbocyclic aromatic system that has at least oneheteroatom selected from N, O, Si, P, and S as a ring-forming atom, inaddition to 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group”as used herein refers to a divalent group having a carbocyclic aromaticsystem that has at least one heteroatom selected from N, O, Si, P, and Sas a ring-forming atom, in addition to 1 to 60 carbon atoms.Non-limiting examples of the C₁-C₆₀ heteroaryl group include a pyridinylgroup, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, and an isoquinolinyl group. Whenthe C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group eachinclude two or more rings, the rings may be condensed with each other.

The term “C₆-C₆₀ aryloxy group” as used herein refers to -OA₁₀₂ (whereinA₁₀₂ is the C₆-C₆₀ aryl group), and a C₆-C₆₀ arylthio group used hereinindicates -SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as usedherein refers to a monovalent group (for example, having 8 to 60 carbonatoms) having two or more rings condensed with each other, only carbonatoms as ring-forming atoms, and containing at least one non-aromaticring in its entire molecular structure. A detailed example of themonovalent non-aromatic condensed polycyclic group is a fluorenyl group.The term “divalent non-aromatic condensed polycyclic group” as usedherein refers to a divalent group having the same structure as themonovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein refers to a monovalent group (for example, having 1 to 60carbon atoms) having two or more rings condensed to each other, at leastone heteroatom selected from N, O, Si, P, and S, other than carbonatoms, as a ring-forming atom, and containing at least one non-aromaticring in its entire molecular structure. An example of the monovalentnon-aromatic condensed heteropolycyclic group is a 9,10-dihydroacridinylgroup. The term “divalent non-aromatic condensed heteropolycyclic group”as used herein refers to a divalent group having the same structure asthe monovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₆₀ carbocyclic group” as used herein refers to amonocyclic or polycyclic group having 5 to 60 carbon atoms in which aring-forming atom is a carbon atom only. The C₅-C₆₀ carbocyclic groupmay be an aromatic carbocyclic group or a non-aromatic carbocyclicgroup. The C₅-C₆₀ carbocyclic group may be a ring, such as benzene, amonovalent group, such as a phenyl group, or a divalent group, such as aphenylene group. In an example embodiment, depending on the number ofsubstituents connected to the C₅-C₆₀ carbocyclic group, the C₅-C₆₀carbocyclic group may be a trivalent group or a quadrivalent group.

The term “C₁-C₆₀ heterocyclic group” as used herein refers to a grouphaving the same structure as the C₅-C₆₀ carbocyclic group, except thatas a ring-forming atom, at least one heteroatom selected from N, O, Si,P, and S is used in addition to carbon (the number of carbon atoms maybe in a range of 1 to 60).

At least one substituent of the substituted C₅-C₆₀ carbocyclic group,the substituted C₁-C₆₀ heterocyclic group, the substituted C₃-C₁₀cycloalkylene group, the substituted C₁-C₁₀ heterocycloalkylene group,the substituted C₃-C₁₀ cycloalkenylene group, the substituted C₁-C₁₀heterocycloalkenylene group, the substituted C₆-C₆₀ arylene group, thesubstituted C₁-C₆₀ heteroarylene group, the substituted divalentnon-aromatic condensed polycyclic group, the substituted divalentnon-aromatic condensed heteropolycyclic group, the substituted C₁-C₆₀alkyl group, the substituted C₂-C₆₀ alkenyl group, the substitutedC₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, thesubstituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group may be selectedfrom:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁),—S(═O)₂(Q₁₁), and —P(═O)(Q₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and—P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently beselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroarylgroup, a monovalent non-aromatic condensed polycyclic group, amonovalent non-aromatic condensed heteropolycyclic group, a C₁-C₆₀ alkylgroup substituted with at least one selected from deuterium, —F, and acyano group, a C₆-C₆₀ aryl group substituted with at least one selectedfrom deuterium, —F, and a cyano group, a biphenyl group, and a terphenylgroup.

The term “Ph” as used herein represents a phenyl group, the term “Me” asused herein represents a methyl group, the term “Et” as used hereinrepresents an ethyl group, the term “ter-Bu” or “But,” as used herein,represents a tert-butyl group, and the term “OMe” as used hereinrepresents a methoxy group.

The term “biphenyl group” used herein refers to a “phenyl groupsubstituted with a phenyl group. The “biphenyl group” is a “substitutedphenyl group” having a “C₆-C₆₀ aryl group” as a substituent.

The term “terphenyl group” used herein refers to a “phenyl groupsubstituted with a biphenyl group. The “terphenyl group” is a “phenylgroup” having, as a substituent, a “C₆-C₆₀ aryl group substituted with aC₆-C₆₀ aryl group.”

* and *′ used herein, unless defined otherwise, each refer to a bindingsite to a neighboring atom in a corresponding formula.

The following Examples and Comparative Examples are provided in order tohighlight characteristics of one or more embodiments, but it will beunderstood that the Examples and Comparative Examples are not to beconstrued as limiting the scope of the embodiments, nor are theComparative Examples to be construed as being outside the scope of theembodiments. Further, it will be understood that the embodiments are notlimited to the particular details described in the Examples andComparative Examples.

EXAMPLES Evaluation Example 1: Quantum Simulation Analysis

An energy level of a ³MLCT state of Compounds 1 to 7 and Compound A (asComparative Compound) was evaluated by using B3LYP function. In the caseof Ir, LANL2DZ basis set was used, and atoms of C, H, N, and F wereevaluated by using a DFT method of Gaussian program structurallyoptimized at a level of 6-311G(d,p) basis set. The evaluation was basedon the ground state energy, triplet energy, and the ³MC state energylevel value, and E₃ was calculated by Equation 1. Results thereof areshown in Table 1.

TABLE 1 ³MLCT (eV) E₃ (kcal/mol) Compound A 3.28 1.18 Compound 1 3.298.10 Compound 2 3.26 11.12 Compound 3 3.28 8.00 Compound 4 2.67 5.75Compound 5 2.80 19.5 Compound 6 2.80 18.7 Compound 7 2.79 19.7

Referring to Table 1, it can be seen that E₃ of Compounds 1 to 7 wasconsiderably higher than E₃ of Compound A. In Compounds 1 to 7, thetransition probability from the ³MLCT state to the ³MC state (which isthe non-luminescent state) is reduced. Therefore, stability in theexcited state may be enhanced, and the efficiency and lifespan of theorganic light-emitting device including the organometallic compound maybe enhanced.

As described above, an organic light-emitting device including theorganometallic compound according to an embodiment may have a lowdriving voltage, high brightness, high efficiency, and a long lifespan.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. An organic light-emitting device, comprising: afirst electrode; a second electrode facing the first electrode; and anorganic layer between the first electrode and the second electrode andincluding an emission layer, wherein the organic layer includes anorganometallic compound, and the organometallic compound includes ahexadentate ligand bonded to a metal atom (M₁), and an energy level(E_(3MC)) of a ³MC (triplet metal centered state) of the organometalliccompound is higher than an energy level (E_(3MLCT)) of a ³MLCT (tripletmetal-to-ligand charge transfer state) of the organometallic compound.2. The organic light-emitting device as claimed in claim 1, wherein theorganometallic compound satisfies E₃≥5 kcal/mol, and E₃ is defined inEquation 1:E ₃ =∥E _(3MLCT) |−|E _(3MC)∥.  <Equation 1>
 3. The organiclight-emitting device as claimed in claim 1, wherein the emission layerincludes the organometallic compound.
 4. The organic light-emittingdevice as claimed in claim 3, wherein the emission layer emits bluephosphorescence having a wavelength of maximum emission in a range ofabout 440 nm to about 490 nm.
 5. The organic light-emitting device asclaimed in claim 1, wherein the organometallic compound is representedby Formula 1:

wherein, in Formulae 1, 2A, and 2B, M₁ is selected from platinum (Pt),palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh),iridium (Ir), ruthenium (Ru), osmium (Os), titanium (Ti), zirconium(Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm), A₁ toA₆ are each independently selected from a C₅-C₆₀ carbocyclic group and aC₁-C₆₀ heterocyclic group, L₁ to L₆ are each independently selected froma single bond, *—O—*′, *—S—*′, *—C(R₁)(R₂)—*′, *—C(R₁)═*′, *═C(R₁)—*′,*—C(R₁)═C(R₂)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₁)—*′,*—N(R₁)—*′, *—P(R₁)—*′, *—Si(R₁)(R₂)—*′, *—P(R₁)(R₂)—*′, and*—Ge(R₁)(R₂)—*′, a1, a3, and a5 are each independently selected from 1,2, and 3, a2, a4, and a6 are each independently selected from 0, 1, 2,and 3, when a2 is 0, A₂ and A₃ are not linked, when a4 is 0, A₄ and A₅are not linked, when a6 is 0, A₆ and A₁ are not linked, Y₁ to Y₆ areeach independently N or C, T₁ to T₆ are each independently selected froma single bond, *—O—*′, and *—S—*′, A₁, A₃, and A₅ are linked via aclipping linker represented by Formula 2A or 2B, X₁ is linked to X₁₀ inFormula 2A or 2B, X₂ is linked to X₂₀ in Formula 2A or 2B, X₃ is linkedto X₃₀ in Formula 2A or 2B, Y₁₀, Y₂₀, Y₃₀, and Y₄₀ are eachindependently N or C(R₃), L₁₀, L₂₀, and L₃₀ are each independentlyselected from a single bond, *—O—*′, *—S—*′, *—C(R₄)(R₅)—*′, *—C(R₄)═*′,*═C(R₄)—*′, *—C(R₄)═C(R₅)—*′, *—C(O)—*′, *—C(═S)—*′, *—C≡C—*′,*—B(R₄)—*′, *—N(R₄)—*′, *—P(R₄)—*′, *—Si(R₄)(R₅)—*′, *—P(R₄)(R₅)—*′, and*—Ge(R₄)(R₅)—*′, a10, a20, and a30 are each independently selected from0, 1, 2, 3, 4, and 5, R₁ to R₅, R₁₀, R₂₀, R₃₀, R₄₀, R₅₀, and R₆₀ areeach independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a substituted or unsubstitutedC₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group,a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₀₁ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted C₁-C₆₀ hetero aryloxy group, asubstituted or unsubstituted C₁-C₆₀ hetero arylthio group, a substitutedor unsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —B(Q₁)(Q₂), —N(Q₁)(Q₂),—P(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)(Q₁), —S(═O)₂(Q₁), —P(═O)(Q₁)(Q₂), and—P(═S)(Q₁)(Q₂), R₁ and R₁₀; R₁ and R₂₀; R₁ and R₃₀; R₁ and R₄₀; R₁ andR₅₀; or R₁ and R₆₀ are optionally linked to form a substituted orunsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstitutedC₁-C₆₀ heterocyclic group, b10, b20, b30, b40, b50, and b60 are eachindependently selected from 1, 2, 3, 4, 5, 6, 7, and 8, * and *′ eachindicate a binding site to a neighboring atom, at least one substituentof the substituted C₅-C₆₀ carbocyclic group, the substituted C₁-C₆₀heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substitutedC₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, thesubstituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₁-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃),—N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and—P(═O)(Q₁₁)(Q₁₂); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, and a monovalent non-aromatic condensed heteropolycyclic group; aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and—P(═O)(Q₂₁)(Q₂₂); and —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and Q₁ to Q₃, Q₁₁ toQ₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ hetero arylthio group, a monovalent non-aromaticcondensed polycyclic group, a monovalent non-aromatic condensedheteropolycyclic group, a C₁-C₆₀ alkyl group substituted with at leastone selected from deuterium, —F, and a cyano group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from deuterium, —F, and a cyanogroup, a biphenyl group, and a terphenyl group.
 6. The organiclight-emitting device as claimed in claim 1, wherein the first electrodeis an anode, the second electrode is a cathode, the organic layerincludes a hole transport region between the first electrode and theemission layer and an electron transport region between the emissionlayer and the second electrode, the hole transport region includes atleast one layer selected from a hole injection layer, a hole transportlayer, a buffer layer, an emission auxiliary layer, and an electronblocking layer, and the electron transport region includes at least onelayer selected from a hole blocking layer, an electron transport layer,and an electron injection layer.
 7. An organometallic compound,comprising: a hexadentate ligand bonded to a metal atom, wherein anenergy level (E_(3MC)) of a ³MC (triplet metal centered state) of theorganometallic compound is higher than an energy level (E_(3MLCT)) of a³MLCT (triplet metal-to-ligand charge transfer state) of theorganometallic compound.
 8. The organometallic compound as claimed inclaim 7, wherein the organometallic compound satisfies E₃≥5 kcal/mol,and E₃ is defined in Equation 1:E ₃ =∥E _(3MLCT) |−|E _(3MC)∥.  <Equation 1>
 9. An organometalliccompound represented by Formula 1:

wherein, in Formulae 1, 2A, and 2B, M₁ is selected from platinum (Pt),palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh),iridium (Ir), ruthenium (Ru), osmium (Os), titanium (Ti), zirconium(Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm), A₁ toA₆ are each independently selected from a C₅-C₆₀ carbocyclic group and aC₁-C₆₀ heterocyclic group, L₁ to L₆ are each independently selected froma single bond, *—O—*′, *—S—*′, *—C(R₁)(R₂)—*′, *—C(R₁)═*′, *═C(R₁)—*′,*—C(R₁)═C(R₂)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₁)—*′,*—N(R₁)—*′, *—P(R₁)—*′, *—Si(R₁)(R₂)—*′, *—P(R₁)(R₂)—*′, and*—Ge(R₁)(R₂)—*′, a1, a3, and a5 are each independently selected from 1,2, and 3, a2, a4, and a6 are each independently selected from 0, 1, 2,and 3, when a2 is 0, A₂ and A₃ are not linked, when a4 is 0, A₄ and A₅are not linked, when a6 is 0, A₆ and A₁ are not linked, Y₁ to Y₆ areeach independently N or C, T₁ to T₆ are each independently selected froma single bond, *—O—*′, and *—S—*′, A₁, A₃, and A₅ are linked via aclipping linker represented by Formula 2A or 2B, X₁ is linked to X₁₀ inFormula 2A or 2B X₂ is linked to X₂₀ in Formula 2A or 2B, X₃ is linkedto X₃₀ in Formula 2A or 2B, Y₁₀, Y₂₀, Y₃₀, and Y₄₀ are eachindependently N or C(R₃), L₁₀, L₂₀, and L₃₀ are each independentlyselected from a single bond, *—O—*′, *—S—*′, *—C(R₄)(R₅)—*′, *—C(R₄)═*′,*═C(R₄)—*′, *—C(R₄)═C(R₅)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′,*—B(R₄)—*′, *—N(R₄)—*′, *—P(R₄)—*′, *—Si(R₄)(R₅)—*′, *—P(R₄)(R₅)—*′, and*—Ge(R₄)(R₅)—*′, a10, a20, and a30 are each independently selected from0, 1, 2, 3, 4, and 5, R₁ to R₅, R₁₀, R₂₀, R₃₀, R₄₀, R₅₀, and R₆₀ areeach independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a substituted or unsubstitutedC₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group,a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted C₁-C₆₀ hetero aryloxy group, asubstituted or unsubstituted C₁-C₆₀ hetero arylthio group, a substitutedor unsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —B(Q₁)(Q₂), —N(Q₁)(Q₂),—P(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)(Q₁), —S(═O)₂(Q₁), —P(═O)(Q₁)(Q₂), and—P(═S)(Q₁)(Q₂), R₁ and R₁₀; R₁ and R₂₀; R₁ and R₃₀; R₁ and R₄₀; R₁ andR₅₀; or R₁ and R₆₀ are optionally linked to form a substituted orunsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstitutedC₁-C₆₀ heterocyclic group, b10, b20, b30, b40, b50, and b60 are eachindependently selected from 1, 2, 3, 4, 5, 6, 7, and 8, * and *′ eachindicate a binding site to a neighboring atom, at least one substituentof the substituted C₅-C₆₀ carbocyclic group, the substituted C₁-C₆₀heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substitutedC₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, thesubstituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₁-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃),—N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and—P(═O)(Q₁₁)(Q₁₂); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, and a monovalent non-aromatic condensed heteropolycyclic group; aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and—P(═O)(Q₂₁)(Q₂₂); and —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and Q₁ to Q₃, Q₁₁ toQ₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ hetero arylthio group, a monovalent non-aromaticcondensed polycyclic group, a monovalent non-aromatic condensedheteropolycyclic group, a C₁-C₆₀ alkyl group substituted with at leastone selected from deuterium, —F, and a cyano group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from deuterium, —F, and a cyanogroup, a biphenyl group, and a terphenyl group.
 10. The organometalliccompound as claimed in claim 9, wherein M₁ is selected from Pt, Pd, Cu,Ag, Au, and Ir.
 11. The organometallic compound as claimed in claim 9,wherein A₁, A₃, and A₅ is a 5-membered heterocyclic group; or a C₁-C₆₀condensed heteropolycyclic group including a 5-membered heterocyclicgroup, and A₂, A₄, and A₆ is a 6-membered carbocyclic group, a6-membered heterocyclic group, a C₆-C₆₀ condensed polycyclic groupincluding a 6-membered carbocyclic group, a C₆-C₆₀ condensedheteropolycyclic group including a 6-membered carbocyclic group, or aC₁-C₆₀ condensed heteropolycyclic group including a 6-memberedheterocyclic group.
 12. The organometallic compound as claimed in claim9, wherein A₂, A₄, and A₆ is selected from Formulae 2-1 to 2-9, and A₁,A₃, and A₅ is selected from Formulae 2-10 to 2-43:

wherein, in Formulae 2-1 to 2-43, X₂₁ to X₂₃ are each independentlyselected from C(R₂₄) and C—*, wherein at least two of X₂₁ to X₂₃ is eachindependently C—*, X₂₄ is N—*, X₂₅ and X₂₆ are each independentlyselected from C(R₂₄) and C—*, wherein at least one of X₂₅ and X₂₆ isC—*, X₂₇ and X₂₈ are each independently selected from N, N(R₂₅), andN—*, and X₂₉ is selected from C(R₂₄) and C—*, wherein i) at least one ofX₂₇ and X₂₈ is N—* and X₂₉ is C—*, or ii) X₂₇ and X₂₈ are each N—* andX₂₉ is C(R₂₄), R₂₁ to R₂₅ are respectively the same as described inconnection with R₁₀ of Formula 1, b21 is selected from 1, 2, and 3, b22is selected from 1, 2, 3, 4, and 5, b23 is selected from 1, 2, 3, and 4,b24 is selected from 1 and 2, and * indicates a binding site to aneighboring atom.
 13. The organometallic compound as claimed in claim 9,wherein L₁ to L₆ are each independently selected from a single bond,*—O—*′, *—S—*′, *—C(R₁)(R₂)—*′, *—C(R₁)═*′, *═C(R₁)—*′,*—C(R₁)═C(R₂)—*′, *—C(═O)—*′, *—C(═S)—*′, and *—N(R₁)—*′, a1, a3, and a5are each independently 1, and a2, a4, and a6 are each independently 0or
 1. 14. The organometallic compound as claimed in claim 9, wherein Y₁,Y₃, and Y₅ are each independently C or N, and Y₂, Y₄, and Y₆ are eachindependently C.
 15. The organometallic compound as claimed in claim 9,wherein each of T₁ to T₆ is a single bond.
 16. The organometalliccompound as claimed in claim 9, wherein Y₁₀, Y₂₀, and Y₃₀ are eachindependently C(R₃).
 17. The organometallic compound as claimed in claim9, wherein L₁₀, L₂₀, and L₃₀ are each independently *—C(R₄)(R₅)—*′,*—C(R₄)═*′, *═C(R₄)—*′, or *—C(R₄)═C(R₅)—*′, and a10, a20, and a30 areeach independently 1 or
 2. 18. The organometallic compound as claimed inclaim 9, wherein R₁ to R₅ are each independently selected from:hydrogen, deuterium, —F, —Cl, —Br, —I, a cyano group, a C₁-C₂₀ alkylgroup, and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀alkoxy group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a cyano group, a phenyl group, and abiphenyl group; a phenyl group, a biphenyl group, a terphenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, and a dibenzocarbazolyl group; and aphenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, an indacenylgroup, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenylgroup, a benzofluorenyl group, a dibenzofluorenyl group, a carbazolylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, and a dibenzocarbazolyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a cyanogroup, a phenyl group, and a biphenyl group, and R₁₀, R₂₀, R₃₀, and R₄₀are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br,—I, a cyano group, a methyl group, an ethyl group, an n-propyl group, anisopropyl group, an n-butyl group, an iso-butyl group, a sec-butylgroup, and a tert-butyl group; a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an iso-butylgroup, a sec-butyl group, and a tert-butyl group, each substituted withat least one selected from deuterium, —F, —Cl, —Br, —I, and a cyanogroup; and a phenyl group, a naphthyl group, and a pyridinyl group. 19.The organometallic compound as claimed in claim 9, wherein a ligand forM₁ in Formula 1 is represented by Formula 1-1 or 1-2:

wherein, in Formulae 1-1 and 1-2, A₁ to A₆, L₁, L₃, L₅, a1, a3, a5, Y₁₀,Y₂₀, Y₃₀, Y₄₀, L₁₀, L₂₀, L₃₀, R₁ to R₅, R₁₀, R₂₀, R₃₀, R₄₀, R₅₀, R₆₀,b10, b20, b30, b40, b50, and b60 are respectively the same as describedfor Formula 1, Y₁ to Y₆ are each independently N or C, and Y₁ to Y₆ arebound to M₁ in Formula
 1. 20. The organometallic compound as claimed inclaim 9, wherein the organometallic compound is selected from Compounds1 to 28: